JP2021096275A - Image forming apparatus - Google Patents

Abstract

To provide an image forming apparatus that can prevent interruption of a toner installation mode which causes a toner in a developing device to absorb moisture and occurrence of an image defect associated therewith.SOLUTION: An image forming apparatus comprises: an image carrier; an exchangeable developing device that uses a one-component developer composed of a magnetic toner; a toner amount detection sensor that detects an amount of toner in the developing device; a toner container that stores a toner to be supplied to the developing device; and a control unit. When a toner installation mode is selected which is for supplying a larger amount of toner than normal supply from the toner container to the developing device, the control unit calculates an amount of toner T1 necessary for execution of the toner installation mode and an amount of toner T2 remaining in the toner container, and when T1>T2 is satisfied, inhibits the execution of the toner installation mode.SELECTED DRAWING: Figure 4

Description

The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile using an electrophotographic process, and more particularly to an image forming apparatus capable of supplying toner to a developing apparatus.

Generally, in a one-component developing type image forming apparatus using a magnetic one-component developer consisting of only magnetic toner, when the user replaces the developing apparatus, toner is supplied (installed) from the toner container into a new developing apparatus. The method is known. Further, in the image forming apparatus having the toner amount detecting sensor, the toner supply amount from the toner container to the developing apparatus is controlled according to the output value of the toner amount detecting sensor.

On the other hand, some developing devices to be replaced do not have an individual identification function such as an IC tag for cost reduction. In such a developing device, it is not possible to determine whether the developing device has been replaced or whether it is a new product or a used product. Therefore, regardless of whether or not there is toner in the developing device, the toner installation mode is set for toner filling. Will be executed. That is, since it is not possible to confirm whether or not the developing device is new when the toner installation mode is activated, it is not possible to determine whether or not the toner installation mode is performed by replacing the developing device.

Therefore, for example, when there is no toner in the unit such as a new developing device, it is necessary to replenish the toner from the toner container, but when using it with the toner in the developing device, replenish the toner. I rarely need it. That is, the required amount of toner in the toner installation mode varies depending on the usage status of the developing device.

Patent Document 1 describes a developer, a toner container including data indicating whether it is an installation toner container or a replacement toner container, and a memory for storing values of remaining amount-related items, and toner in the developer. It includes a replenishment unit for replenishment, a read / write unit for reading and writing memory, and a control unit that gradually reduces the current value of remaining amount related items according to the number of printed sheets. When the installation is performed, the value based on the remaining amount of toner after installation is stored in the memory, and the value based on the remaining amount of toner before installation is stored in the memory when the toner container for installation is installed after installation. The image forming apparatus is disclosed.

Japanese Unexamined Patent Publication No. 2017-15754

However, when the method of Patent Document 1 is used, the toner in the toner container is reduced when the developing device is empty, but the toner in the toner container is not reduced when the developing device is filled with toner. Therefore, there is a problem that the remaining amount of toner in the toner container cannot be measured correctly if there is no method for detecting the amount of toner in the developing device.

Further, the method of Patent Document 1 is devised so that the calculation of the remaining amount of toner in the toner container functions correctly by detecting the specifications at the time of replacing the toner container. This content is based on the premise that one toner container can cover the toner for toner installation, but in the market, toner installation may be performed using a used toner container. Therefore, even if all the toner in the toner container is replenished to the developing device, the amount of toner in the developing device may not be satisfied to the specified amount.

In this case, it is necessary to prepare a new toner container, but if there is no spare toner container, the toner container will be ordered from that point, so the toner replenished halfway in the developing device will be added. It will be left as it is until the toner container is prepared. During this period, if a history such as a change in the toner charge amount such as moisture absorption is added, a charge amount difference with the toner replenished from the newly prepared toner container will occur, so that image fog and image density will occur. There was a risk of problems such as deterioration.

In view of the above problems, it is an object of the present invention to provide an image forming apparatus capable of suppressing the absorption of toner in the developing apparatus due to the interruption of the toner installation mode and the occurrence of image defects associated therewith.

In order to achieve the above object, the first configuration of the present invention is an image forming apparatus including an image carrier, a developing apparatus, a toner amount detection sensor, a toner container, and a control unit. A photosensitive layer is formed on the surface of the image carrier. The developing apparatus has a developing container that is replaceable and stores a one-component developer made of magnetic toner, and a toner carrier that supports the toner in the developing container, and is formed on the surface of the image carrier. Toner is adhered to the created electrostatic latent image to form a toner image. The toner amount detection sensor detects the amount of toner in the developing device. The toner container stores toner for replenishing the developing device. The control unit controls the supply of toner from the toner container to the developing device. The control unit has a normal replenishment mode in which toner is replenished from the toner container to the developing device based on the detection result of the toner amount detection sensor, and a toner installation mode in which a larger amount of toner is replenished from the toner container to the developing device than the normal replenishment. It is feasible. When the toner installation mode is selected, the control unit calculates the amount of toner T1 required to execute the toner installation mode and the remaining amount of toner T2 in the toner container, and if T1> T2, the toner installation mode is selected. Prohibit execution.

According to the first configuration of the present invention, if the remaining amount of toner in the toner container is not more than the amount of toner required for toner installation from the toner container to the developing device, the execution of the toner installation mode is prohibited. , There is no possibility that the image forming apparatus is left for a long time during toner installation. Therefore, it is possible to suppress the occurrence of image defects after the completion of the toner installation due to the toner in the developing apparatus absorbing moisture during the toner installation.

Schematic cross-sectional view showing the overall configuration of the image forming apparatus 100 according to the embodiment of the present invention. Side sectional view of the developing apparatus 16 used in the image forming apparatus 100 of the present embodiment. A block diagram showing a control path of the image forming apparatus 100 of the present embodiment. A flowchart showing a control example of the toner installation mode in the image forming apparatus 100 of the present embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing an overall configuration of an image forming apparatus 100 according to an embodiment of the present invention. As shown in FIG. 1, the image forming apparatus (here, a monochrome printer) 100 is provided with a paper feed cassette 2 for accommodating paper loaded in the lower part of the main body. Above the paper feed cassette 2, a paper transport path 4 is formed which extends substantially horizontally from the front of the main body to the rear of the main body and further extends upward to reach the paper ejection portion 3 formed on the upper surface of the main body. A pickup roller 5, a feed roller 6, an intermediate transport roller 7, a resist roller pair 8, an image forming portion 9, a fixing portion 10, and a discharge roller pair 11 are arranged in this order from the upstream side along the transport path.

The paper cassette 2 is provided with a paper loading plate 12 that is rotatably supported by a rotating fulcrum 12a provided at the rear end in the paper transport direction with respect to the paper cassette 2. The paper loaded on the 12 is pressed by the pickup roller 5. Further, a retard roller 13 is arranged at the front portion of the paper feed cassette 2 so as to be in pressure contact with the feed roller 6. When a plurality of sheets of paper are fed by the pickup roller 5 at the same time, the sheets are separated by the feed roller 6 and the retard roller 13, and only the topmost sheet is conveyed.

The paper separated by the feed roller 6 and the retard roller 13 is transferred to the resist roller pair 8 by changing the transport direction to the rear of the apparatus by the intermediate transport roller 7, and the timing is adjusted by the resist roller pair 8 to obtain an image. It is conveyed to the forming portion 9.

The image forming unit 9 forms a predetermined toner image on the paper by an electrophotographic process. The image forming unit 9 includes a photoconductor drum 14 which is an image carrier rotatably supported in the clockwise direction in FIG. 1, and a charging device 15 and a developing device 16 arranged around the photoconductor drum 14. It is composed of a cleaning device 17, a transfer roller 18 arranged so as to face the photoconductor drum 14 with the paper transport path 4 interposed therebetween, and an exposure device (laser scanning unit) 19 arranged above the photoconductor drum 14. .. Above the developing device 16, a toner container 20 for supplying toner to the developing device 16 is arranged as needed.

The photoconductor drum 14 is, for example, an aluminum drum in which a photosensitive layer is laminated. As the photosensitive material forming the photosensitive layer, an amorphous silicon photosensitive member or an organic photosensitive member (OPC photosensitive member) is used. As the charging device 15, a scorotron charging device using a corona discharge or a contact charging type charging device using a charging roller is used. By applying a predetermined charging voltage to the charging device 15, the surface of the photoconductor drum 14 is uniformly charged with a predetermined polarity (same polarity as the toner) and potential.

Next, an electrostatic latent image is formed by exposing the photoconductor drum 14 with a laser beam from an exposure device 19 based on image data input from a higher-level device such as a personal computer (hereinafter referred to as a personal computer) to attenuate the charge. To. Then, the developing device 16 adheres the toner to the electrostatic latent image to form the toner image on the surface of the photoconductor drum 14.

The toner image formed on the photoconductor drum 14 is transferred by the transfer roller 18 to the paper supplied to the transfer position formed at the nip portion between the photoconductor drum 14 and the transfer roller 18. The paper on which the toner image is transferred is separated from the photoconductor drum 14 and conveyed toward the fixing portion 10. The fixing portion 10 is arranged on the downstream side of the image forming portion 9 with respect to the paper conveying direction, and the paper on which the toner image is transferred in the image forming portion 9 is provided on the heating roller 21 provided on the fixing portion 10 and the fixing portion 10. The toner image transferred to the paper is fixed by being sandwiched and heated by the pressure roller 22 which is pressed against the heating roller 21.

Then, the paper that has passed through the image forming unit 9 and the fixing unit 10 is discharged to the paper ejection unit 3 by the ejection roller pair 11. On the other hand, the toner remaining on the surface of the photoconductor drum 14 is removed by the cleaning device 17. Then, the photoconductor drum 14 is charged again by the charging device 15, and the image formation is performed in the same manner thereafter.

FIG. 2 is a side sectional view of the developing device 16 mounted on the image forming device 100 of the present embodiment. The developing device 16 is removable from the image forming device 100, and as shown in FIG. 2, a container body 31a and a container body 31a in which a magnetic one-component developer (hereinafter referred to as toner) made of magnetic toner is housed. A first stirring transfer screw 32, a second stirring transfer screw 33, a developing roller 35, and a regulating blade 36 are contained in a developing container 31 composed of a cover 31b for sealing the toner contained in the container so as not to leak to the outside. It is provided.

The inside of the container body 31a is divided into a first storage chamber 38 and a second storage chamber 39 by a partition wall 37 extending in the longitudinal direction, and a first stirring transfer screw 32 is provided in the first storage chamber 38. A second stirring transfer screw 33 is arranged in each of the second storage chamber 39. Further, the partition walls 37 are not provided at both ends of the container body 31a in the longitudinal direction (direction perpendicular to the paper surface), and this portion is formed between the first storage chamber 38 and the second storage chamber 39 by toner. It is a moving passage.

The first stirring transfer screw 32 and the second stirring transfer screw 33 are composed of rotating shafts 32a and 33a and spiral blades 32b and 33b integrally formed on the outer peripheral surfaces of the rotating shafts 32a and 33a, respectively. It is rotatably supported in the container body 31a so as to be parallel. Then, the first stirring transfer screw 32 and the second stirring transfer screw 33 rotate in a predetermined direction to circulate and convey the toner in the first storage chamber 38 and the second storage chamber 39. Further, the cover 31b is supplied with toner from the toner container 20 (see FIG. 1) so that the toner can be replenished in the container body 31a according to the detection result of the toner amount detection sensor 40 (see FIG. 3). A mouth (not shown) is provided.

The developing roller 35 is rotatably supported in the first storage chamber 38 so as to be substantially parallel to the first stirring transfer screw 32 and the second stirring transfer screw 33. A magnet roller (not shown) composed of permanent magnets having a plurality of magnetic poles is fixed inside the developing roller 35, and when the developing roller 35 rotates according to the rotation of the photoconductor drum 14, the magnet roller of the developing roller 35 Toner is adhered (supported) to the surface of the developing roller 35 by magnetic force to form a toner layer. Then, the toner adhering to the developing roller 35 in the predetermined developing region has the surface potential of the photoconductor drum 14 and the developing voltage applied to the developing roller 35 (for example, DC voltage Vdc = 280V, AC voltage Vpp = 1.7 kV, frequency). Due to the potential difference from 2.3 kHz), it flies to the photoconductor drum 14 and adheres to the photosensitive layer, and a toner image is formed on the surface of the photoconductor drum 14.

The regulation blade 36 regulates the amount of toner supplied to the photoconductor drum 14, that is, the amount of toner adhering to the developing roller 35, and for example, a magnetic material such as SUS (stainless steel) is used. The regulating blade 36 is arranged so as to form a predetermined gap between the tip thereof and the developing roller 35, and the developing roller is formed by the distance between the regulating blade 36 and the developing roller 35 and the magnetic field generated in the gap. The amount of toner adhering to 35 is regulated, and a thin layer of toner of several tens of microns is formed on the surface of the developing roller 35.

Next, the control path of the image forming apparatus 100 will be described. FIG. 3 is a block diagram showing an example of a control path used in the image forming apparatus 100 of the present embodiment. Since various controls are performed for each part of the image forming apparatus 100 in using the image forming apparatus 100, the control path of the entire image forming apparatus 100 becomes complicated. Therefore, here, the part of the control path required for the implementation of the present invention will be mainly described.

The control unit 90 includes a CPU (Central Processing Unit) 91 as a central processing unit, a ROM (Read Only Memory) 92 as a read-only storage unit, a RAM (Random Access Memory) 93 as a readable and writable storage unit, and a temporary storage unit. A plurality of (here, two) I /s for transmitting a control signal to each device in the temporary storage unit 94 and the image forming device 100 for storing image data and the like and receiving an input signal from the operation unit 80. It has at least an F (interface) 96. The control unit 90 can be arranged at any place inside the image forming apparatus 100.

The ROM 92 contains data such as a control program for the image forming apparatus 100, numerical values necessary for control, and the like that are not changed during use of the image forming apparatus 100. The RAM 93 stores necessary data generated during the control of the image forming apparatus 100, data temporarily required for controlling the image forming apparatus 100, and the like. Further, in the RAM 93, a target value (reference value) of the toner filling amount in the developing apparatus 16 used for calculating the toner amounts T1 and T2 when the toner installation mode described later is executed, and the initial toner storage amount of the toner container 20. , The average print rate from the start of use of the toner container 20, the cumulative number of prints, and the like are also stored.

Further, the control unit 90 transmits a control signal from the CPU 91 to each part and the device in the image forming apparatus 100 through the I / F 96. Further, a signal indicating the state and an input signal from each part and the device are transmitted to the CPU 91 through the I / F 96. The parts and devices controlled by the control unit 90 include, for example, a paper feed cassette 2, a fixing unit 10, a developing device 16, an exposure device 19, a toner container 20, a toner amount detection sensor 40, a toner replenishment motor 41, and a voltage control circuit. 51, an image input unit 60, an operation unit 80, a communication unit 83, and the like can be mentioned.

The toner amount detection sensor 40 is provided in the vicinity of the mounting portion of the developing device 16 in the image forming apparatus 100, and detects the amount of toner in the developing device 16. Depending on the detection result of the toner amount detection sensor 40, the toner stored in the toner container 20 (see FIG. 1) is transferred to the developing container 31 through a toner replenishment port (not shown) provided on the cover 31b of the developing container 31. Supplied in. As the toner amount detection sensor 40, a magnetic permeability sensor that detects the magnetic permeability of toner in the developing apparatus 16 is used. The toner amount detection sensor 40 can also be arranged on the developing device 16 side.

Further, as will be described later, since the toner amount required for toner installation is calculated based on the detection result of the toner amount detection sensor 40, the toner amount detection sensor 40 needs to accurately detect the toner amount in the developing device 16. is there. Therefore, it is preferable to use the toner amount detection sensor 40 having a wide detection area (detection surface) that is included in the detection range from the bottom to the top of the developing container 31.

The toner replenishment motor 41 replenishes the toner stored in the toner container 20 to the developing device 16 at a predetermined speed. In the present embodiment, the toner amount detection sensor 40 detects the magnetic permeability of the developer, and the voltage value corresponding to the detection result is output to the control unit 90. The control unit 90 determines the amount of toner in the developing device 16 from the output value of the toner amount detecting sensor 40, transmits a control signal to the toner replenishment motor 41 according to the determined toner amount, and the developing device from the toner container 20. A predetermined amount of toner is replenished (normally replenished) to 16.

The voltage control circuit 51 is connected to a charging voltage power supply 52, a developing voltage power supply 53, and a transfer voltage power supply 54, and operates each of these power supplies by an output signal from the control unit 90, and each of these power supplies is voltage controlled. By the control signal from the circuit 51, the charging voltage power supply 52 applies a predetermined voltage to the charging device 15, the developing voltage power supply 53 applies a predetermined voltage to the developing roller 35 in the developing device 16, and the transfer voltage power supply 54 applies a predetermined voltage to the transfer roller 18. ..

The image input unit 60 is a receiving unit that receives image data transmitted from a personal computer or the like. The image signal input from the image input unit 60 is converted into a digital signal and then sent to the temporary storage unit 94.

The operation unit 80 is provided with a liquid crystal display unit 81 and LEDs 82 for indicating various states, and is adapted to indicate the state of the image forming apparatus 100 and to display the image forming status and the number of printed copies. Various settings of the image forming apparatus 100 are performed from the printer driver of the personal computer.

In addition, the operation unit 80 has a start button instructing the user to start image formation, a stop / clear button used when stopping image formation, and when various settings of the image forming device 100 are set to the default state. There is a reset button etc. used for.

The communication unit 83 performs wired or wireless data communication with an external device such as a personal computer via a communication network such as the Internet or LAN. In the present embodiment, as will be described later, the communication unit 83 can transmit the order data of the new toner container 20 to the distribution center, the dealer, or the like.

In the image forming apparatus 100 of the present embodiment, when the toner in the developing apparatus 16 is exhausted, the developing apparatus 16 is removed and replaced with an unused developing apparatus 16, and the toner is replenished at the time of image formation (normal replenishment). A toner installation mode is executed in which a larger amount of toner is supplied to the developing device 16. Alternatively, even when the developing device 16 is not replaced, for example, when the toner container 20 is replaced and new toner is replenished, the toner installation mode may be executed in order to stabilize the charged state of the toner. .. At this time, if the developing device 16 does not have an individual discrimination function such as an IC tag, it cannot be determined whether or not the toner in the developing device 16 is an empty unused product.

Further, the toner installation mode needs to be continued until a predetermined amount of toner is filled in the developing device 16. However, when the toner installation mode is executed with the remaining amount of toner in the toner container 20 being low, even if all the toner in the toner container 20 is replenished in the developing device 16, the toner is stored in the developing device 16. The toner installation mode is paused because the toner is not filled in a fixed amount. As a result, the image forming apparatus 100 is left for a long time in a state where the toner installation is not completed, and there is a possibility that problems such as image fog and image density decrease may occur after the toner container 20 is replaced and the installation is completed. ..

Therefore, in the present embodiment, when the toner installation mode is selected, the amount of toner T1 required to fill the developing apparatus 16 with a predetermined amount of toner and the remaining amount of toner T2 in the toner container 20 are calculated. Then, when the amount of toner T1 required for toner installation is larger than the remaining amount of toner T2, the execution of the toner installation mode is prohibited.

FIG. 4 is a flowchart showing a control example of the toner installation mode in the image forming apparatus 100 of the present embodiment. The procedure for executing the toner installation will be described along the steps of FIG. 4 with reference to FIGS. 1 to 3.

First, the control unit 90 determines whether or not the toner installation mode has been selected (step S1). When the toner installation mode is selected (Yes in step S1), the toner amount detection sensor 40 detects the amount of toner in the developing device 16 (step S2). The detection result of the toner amount detection sensor 40 is transmitted to the control unit 90.

Next, the control unit 90 calculates the toner amount T1 required for toner installation based on the detected toner amount in the developing device 16 (step S3). The toner amount T1 is calculated by subtracting the detected toner amount from the target value of the toner filling amount of the developing device 16 stored in the RAM 93 (or ROM 92).

Next, the control unit 90 calculates the remaining amount of toner T2 in the toner container 20 (step S4). The toner remaining amount T2 is calculated by subtracting the toner amount consumed by the printing operation (toner consumption amount) from the toner remaining amount (initial toner storage amount) at the start of use of the toner container 20 stored in the RAM 93 (or ROM 92). .. The toner consumption is calculated based on the average print rate and the cumulative number of prints from the start of use of the toner container 20 stored in the RAM 93 (or ROM 92).

Next, the control unit 90 determines whether or not T1 ≦ T2 (step S5). When T1 ≦ T2 (Yes in step S3), the remaining amount of toner T2 in the toner container 20 is equal to or more than the amount of toner T1 required for toner installation in the developing device 16, so that the toner container 20 is transferred to the developing device 16. The toner installation mode for replenishing toner is started (step S6).

After that, the control unit 90 determines whether or not the toner installation is completed, that is, whether or not the toner amount detection sensor 40 has detected that the toner has been replenished to a specified level (step S7). If the toner has not been replenished to the specified level (No in step S7), the toner installation is continued. When the toner has been replenished to a specified level (Yes in step S7), the process ends.

On the other hand, when T1> T2 (No in step S3), the remaining amount of toner T2 in the toner container 20 is less than the amount of toner T1 required for toner installation in the developing device 16, so the toner installation mode is started. Instead, the liquid crystal display unit 81 displays the insufficient amount of toner remaining in the toner container 20 (step S8). Then, the communication unit 83 automatically orders the replacement toner container 20 (step S9), and the process is completed.

According to the control example described above, if the remaining amount of toner in the toner container 20 is not more than the amount of toner required for toner installation from the toner container 20 to the developing device 16, the execution of toner installation is stopped. There is no possibility that the image forming apparatus 100 is left for a long time during toner installation. Therefore, it is possible to suppress the occurrence of image defects after the completion of the toner installation due to the toner in the developing apparatus 16 absorbing moisture during the toner installation.

If the remaining amount of toner in the toner container 20 is not more than the amount of toner required for toner installation, the liquid crystal display 81 indicates that the remaining amount of toner in the toner container 20 is insufficient, so that the user is notified of the remaining amount of toner in the toner container 20. Can be notified to encourage the exchange of toner. Further, by automatically ordering the replacement toner container 20 by the communication unit 83, it is not necessary to manage the inventory of the toner container 20.

Others The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the dimensions, materials, shapes, relative arrangements, and the like of the components described in the above-described embodiment are not intended to limit the scope of the present invention to the specific description unless otherwise specified, and are merely explanatory examples. Not too much.

Further, the present invention is not limited to the monochrome printer shown in FIG. 1, and includes analog monochrome copiers, rotary or tandem color copiers, color printers, copiers such as analog monochrome copiers, facsimiles and the like. Of course, it can be applied to various image forming apparatus provided with a developing apparatus in which a one-component developer is replenished from a toner container.

The present invention can be used for an image forming apparatus capable of supplying toner to a detachable developing apparatus. By utilizing the present invention, it is possible to provide an image forming apparatus capable of suppressing the absorption of toner in the developing apparatus due to the interruption of the toner installation mode and the occurrence of image defects associated therewith.

14 Photoreceptor drum (image carrier)
15 Charging device 16 Developing device 20 Toner container (toner container)
40 Toner amount detection sensor 80 Operation unit 81 Liquid crystal display unit (notification device)
83 Communication unit 90 Control unit 91 CPU
92 ROM (storage unit)
93 RAM (storage unit)
100 image forming device

Claims (5)

An image carrier with a photosensitive layer formed on its surface,
An electrostatic latent image formed on the surface of the image carrier, which has a developing container for storing a one-component developer made of magnetic toner and a toner carrier for supporting the toner in the developing container. An interchangeable developing device that adheres the toner to form a toner image,
A toner amount detection sensor that detects the amount of toner in the developing device, and
A toner container for storing the toner for replenishing the developing device, and
A control unit that controls the supply of the toner from the toner container to the developing device, and
In an image forming apparatus equipped with
The control unit
Normal replenishment of replenishing the toner from the toner container to the developing device based on the detection result of the toner amount detection sensor, and
It is possible to execute a toner installation mode in which a larger amount of the toner than the normal replenishment is replenished from the toner container to the developing device.
When the toner installation mode is selected, the control unit calculates the amount of toner T1 required to execute the toner installation mode and the remaining amount of toner T2 in the toner container, and if T1> T2, the control unit calculates. An image forming apparatus comprising prohibiting execution of the toner installation mode. A notification device for notifying the state of each part of the image forming apparatus including the toner container is provided.
The image forming apparatus according to claim 1, wherein when T1> T2, the control unit uses the notification device to give a notification prompting the replacement of the toner container. Equipped with a communication unit that can communicate via a network
The image forming apparatus according to claim 1 or 2, wherein the control unit automatically orders the replacement toner container using the communication unit when T1> T2. A storage unit for storing a target value of a toner filling amount of the developing device and an initial toner storage amount of the toner container is provided.
The control unit calculates the toner amount T1 by subtracting the toner amount in the developing device detected by the toner amount detection sensor detection from the target value of the toner filling amount.
The image forming apparatus according to any one of claims 1 to 3, wherein the toner remaining amount T2 is calculated by subtracting the toner consumption amount consumed by the printing operation from the initial toner storage amount. The image forming apparatus according to claim 4, wherein the toner consumption amount is calculated based on an average printing rate and a cumulative number of printed sheets stored in the storage unit from the start of use of the toner container. ..

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